How much risk should fire fighters take to attempt to recover a victim who has no chance of surviving?

In phase contrast microscopy, the function of the phase ring is to:

a. Direct light through its open circular area b. Retard the wavelength of deflected light c. Project the beam of light onto the sample d. Diffract the light from the condenser

In a parallel circuit,

a. Ohm's law does not apply. b. total current flow is equal across its parallel branches. c. the voltage is equal across all branches of the circuit. d. as more resistors are added total resistance increases.